1. Field of the Invention
The present invention relates to electronic equipment with a printer unit and, more particularly, to electronic equipment with a printer unit capable of printing on an internal print form held in the equipment and an external print sheet form disposed on a desk or the like.
2. Description of the Prior Art
Electronic equipment with a printer unit such as a desk-top electronic calculator capable of printing on an internal print roll form (hereinafter referred to as a paper roll) and an external print sheet form (hereinafter referred to as a sheet paper) disposed on a desk or the like has been known. A construction of such a prior art electronic equipment is shown in FIGS. 1-4.
FIG. 1 shows an overall construction of the desk-top calculator with the printer unit. The desk-top calculator generally designated by numeral 1 has a keyboard 2 for entering various inputs on a right upper surface. The keyboard 2 accommodates an arithmetic and logic circuit, a power supply and other circuits. A display 3 for displaying input values and results of the arithmetic operations is provided on a surface of a raised portion at a left half of the desk-top calculator 1.
A window 4 is formed at a rear portion of the left half of the desk-top calculator 1 and a paper cutter 5 is obliquely mounted in the window 4. A paper roll 7 is mounted on a paper roll holder 6 which is mounted at a rear end of the desk-top calculator 1. A leading edge of the paper roll 7 is taken into the desk-top calculator 1 from the rear end thereof and guided externally through a space between the window 4 and a blade 5a of the paper cutter 5.
A lever 9 for switching the printing between the paper roll 7 (first mode) and the sheet paper 8 (second mode) is mounted on one side of the window 4.
Numeral 10 denotes a power switch, numerals 11a and 11b denote column spacing identification marks and a row (line) position identification mark, respectively, numeral 8a denotes characters printed on the sheet paper 8 and numeral 8b denotes print lines.
The desk-top calculator 1 includes a printer unit as shown in FIGS. 2-4.
The printer unit 12 has a hollow type wheel 13. Type belts 14 made of resilient material are mounted on an outer periphery of the type wheel 13. Each of the type belts 14 has types 14a circumferentially arranged at a predetermined pitch. Solenoids 15, one solenoid for each type belt 14, are arranged within the type wheel 13. Each of the solenoids 15 has a hammer 16 associated therewith.
As shown in FIG. 4, by manipulating the lever 9 to engage a gear 19 which is integral with the lever 9, with a gear 18 which is mounted on a rotary shaft 17 of the solenoid 15, the orientation of the hammer 16 is switched between a horizontal position (first mode) shown in FIG. 2 and a vertical position (second mode) shown in FIG. 3.
Numeral 20 denotes a platen, numeral 21 denotes an ink roll numeral 22 denotes an insert port for the paper roll 7, and numeral 23 denotes rolls for feeding the paper roll 7.
The type wheel 13 is driven by a pulse motor (not shown) which is controlled by a control circuit accommodated in the desk-top calculator 1 so that a desired type is positioned at the print position.
By manipulating the lever 9, the hammers 16 are switched between the horizontal position and the vertical position so that the printing is effected on the paper roll 7 or the sheet paper 8. However, this construction has the following disadvantage.
When the lever 9 is manipulated to rotate the hammers 16 in the vertical downward direction to print on the sheet paper 8, the print position is not visible when the desk-top calculator 1 is arranged on the sheet paper 8 because the type wheel 13 is mounted to project slightly from an opening formed on the back side of the desk-top calculator 1. Thus, it is difficult to print at the desired print position.
In order to resolve the above problem, the marks 11a and 11b are arranged on the side of the desk-top calculator 1 at the positions corresponding to the print positions as shown in FIG. 1 to determine by those marks the print positions on the sheet paper 8.
While the print positions can be defined in this manner, a distance between the sheet paper 8 and the type 14a cannot be large because a projection distance of the type 14a when it is impacted by the hammer 16 is very small. Accordingly, when the printing is effected on the paper roll 7, the type 14a is in very close to the sheet paper 8. As a result, the type may contact the desk or the sheet paper 8, or ink may drop thereon and contaminate them, or the type may contact a projected article on the desk and the type wheel may be broken.
Although the desired print position can be attained by using the marks 11a and 11b, such positioning is effective only when the sheet paper 8 is sufficiently larger than the desk-top calculator 1 and indicia such as ruled lines are marked on the sheet paper 8. Printing at the exact print position on a small document such as a slip is very difficult.
Since the marks 11a are also arranged on the side of the desk-top calculator 1 on which the paper roll 7 is mounted, those marks 11a are not visible in determining the print position. Therefore, when printing on the sheet paper 8 on the desk, the paper roll 7 is usually removed from the holder 6 and the holder 6 is accommodated in the desk-top calculator 1.
As a result, when the mode is switched from the paper roll print mode to the sheet paper print mode, the paper roll 7 is first removed from the holder 6, the holder 6 is accommodated in the desk-top calculator 1, the lever 9 is manipulated to rotate the hammers 16 to the vertical position, the desk-top calculator 1 is positioned to the desired print position by the marks 11a and 11b and then the keyboard 2 is manipulated to print the characters. Thus, the operation is very troublesome.
Since the projection distance of the type 14a when it is impacted by the hammer 16 is very small, the distance between the sheet paper 8 and the type 14a must always be constant in order to attain uniform printing.
If the sheet paper 8 includes a small step or the mount position of the printer unit 12 is slightly deviated, the distance between the type 14a and the sheet paper 8 is non-uniform and non-uniform print or broken print will result.